(1) Field of the Invention
This invention relates to a softener composition able to soften many kinds of clothes, fabrics, textiles, hair and the like, and in particular to a highly concentrated softener composition having improved viscosity characteristics.
(2) Description of the Prior Art
Many studies have recently been conducted on softener compositions containing large amounts of softening agent, the so-called highly concentrated-type softeners, intended to replace conventional aqueous softeners which contain only about 4% by weight of cationic softening agent. The main object of these studies has been to reduce the cost of transporting the softener, but many difficulties have been met in the development of highly concentrated-type softeners because the behavior of an aqueous solution containing a cationic softening agent is complicated. In particular, where the softener is in the form of an aqueous solution containing a dispersion of insoluble or slightly soluble cationic agent, a sudden rise of viscosity thereof and water separation therefrom occurs when the content of the cationic agent is made too high, other components are added thereto, or the temperature thereof is changed.
Many methods have been proposed to solve these problems. Among these are, for example, a method (Japanese Patent Pre-examined Publication (KOKAI) No. 51877/1980) in which cationized polyoxyethylene alkylamine and lower alcohol are added to a mixture of quaternary ammonium salt and imidazolinium salt and a method (Japanese Patent Pre-examined Publication (KOKAI) No. 149378/1983) in which an aliphatic amine polyglycol, a lower alcohol and an acid are added to a quaternary ammonium salt.
These methods, however, are insufficient regarding the prevention of a rise in the viscosity of the softener composition and separation of water therefrom by a temperature change where the composition contains cationic softening agent at high concentrations.